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Mapping of individual dislocations with dark-field X-ray microscopy

Jakobsen, A. C. and Simons, Hugh and Ludwig, W. and Yildirim, C. and Leemreize, H. and Porz, Lukas and Detlefs, C. and Poulsen, H. F. (2018):
Mapping of individual dislocations with dark-field X-ray microscopy.
In: Journal of Applied Crystallography, 52 (1), pp. 122-132. ISSN 0021-8898, e-ISSN 1600-5767,
DOI: 10.1107/S1600576718017302,
[Article]

Abstract

This article presents an X-ray microscopy approach for mapping deeply embedded dislocations in three dimensions using a monochromatic beam with a low divergence. Magnified images are acquired by inserting an X-ray objective lens in the diffracted beam. The strain fields close to the core of dislocations give rise to scattering at angles where weak beam conditions are obtained. Analytical expressions are derived for the image contrast. While the use of the objective implies an integration over two directions in reciprocal space, scanning an aperture in the back focal plane of the microscope allows a reciprocal-space resolution of DQ/Q < 5 x10^-5 in all directions, ultimately enabling highprecision mapping of lattice strain and tilt. The approach is demonstrated on three types of samples: a multi-scale study of a large diamond crystal in transmission, magnified section topography on a 140 mm-thick SrTiO3 sample and a reflection study of misfit dislocations in a 120 nm-thick BiFeO3 film epitaxially grown on a thick substrate. With optimal contrast, the half-widths at half-maximum of the dislocation lines are 200 nm.

Item Type: Article
Erschienen: 2018
Creators: Jakobsen, A. C. and Simons, Hugh and Ludwig, W. and Yildirim, C. and Leemreize, H. and Porz, Lukas and Detlefs, C. and Poulsen, H. F.
Title: Mapping of individual dislocations with dark-field X-ray microscopy
Language: English
Abstract:

This article presents an X-ray microscopy approach for mapping deeply embedded dislocations in three dimensions using a monochromatic beam with a low divergence. Magnified images are acquired by inserting an X-ray objective lens in the diffracted beam. The strain fields close to the core of dislocations give rise to scattering at angles where weak beam conditions are obtained. Analytical expressions are derived for the image contrast. While the use of the objective implies an integration over two directions in reciprocal space, scanning an aperture in the back focal plane of the microscope allows a reciprocal-space resolution of DQ/Q < 5 x10^-5 in all directions, ultimately enabling highprecision mapping of lattice strain and tilt. The approach is demonstrated on three types of samples: a multi-scale study of a large diamond crystal in transmission, magnified section topography on a 140 mm-thick SrTiO3 sample and a reflection study of misfit dislocations in a 120 nm-thick BiFeO3 film epitaxially grown on a thick substrate. With optimal contrast, the half-widths at half-maximum of the dislocation lines are 200 nm.

Journal or Publication Title: Journal of Applied Crystallography
Journal volume: 52
Number: 1
Divisions: 11 Department of Materials and Earth Sciences
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences > Material Science > Nonmetallic-Inorganic Materials
Date Deposited: 15 Oct 2020 06:27
DOI: 10.1107/S1600576718017302
Official URL: https://onlinelibrary.wiley.com/iucr/doi/10.1107/S1600576718...
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